Net nitrogen mineralization and nitrification in trembling aspen forest soils on the Boreal Plain

2003 ◽  
Vol 33 (11) ◽  
pp. 2262-2268 ◽  
Author(s):  
N Carmosini ◽  
K J Devito ◽  
E E Prepas
Keyword(s):  
Populus Tremuloides ◽  
N Mineralization ◽  
Growing Season ◽  
Large Contribution ◽  
Net N Mineralization ◽  
Trembling Aspen ◽  
Mineral Horizon ◽  
Net Nitrification ◽  
Winter Activity ◽  
Aspen Forest

In situ net N mineralization and net nitrification rates were measured in organic forest floor (LFH) and mineral horizons of mature and logged trembling aspen (Populus tremuloides Michx.) stands on the Boreal Plain in western Canada. Cumulative May to September mineralization for mature and logged plots was 1354 ± 534 and 1631 ± 1584 mg N·m–2, respectively, in the LFH horizon and 810 ± 394 and –305 ± 3957 mg N·m–2, respectively, in the mineral horizon. Net nitrification in mature and logged plots was 86 ± 142 and 658 ± 435 mg NO3-N·m–2, respectively, in the LFH horizon and 67 ± 50 and 409 ± 325 mg NO3-N·m–2, respectively, in the mineral horizon. Monthly mean NH4-N concentrations in the LFH tended to be higher in logged plots than in mature plots. Winter net N mineralization and nitrification rates in the LFH of mature plots were up to 7% and 11% of growing season net rates, respectively. In comparison, these rates in logged plots were up to 127% and 59% of the growing season net rates, respectively, indicating that winter activity may make a large contribution to annual net mineralization and nitrification after logging.

scholarly journals Effects of experimental freezing on soil nitrogen dynamics in soils from a net nitrification gradient in a nitrogen-saturated hardwood forest ecosystem

2010 ◽  
Vol 40 (3) ◽  
pp. 436-444 ◽  
Author(s):  
Frank S. Gilliam ◽  
Adam Cook ◽  
Salina Lyter
Keyword(s):  
N Mineralization ◽  
Soil Freezing ◽  
N Saturation ◽  
Net N Mineralization ◽  
N Dynamics ◽  
Net Nitrification ◽  
Soil Nitrogen Dynamics ◽  
Soil N Cycle ◽  
N Mineralization Potential ◽  
Fernow Experimental Forest

This study examined effects of soil freezing on N dynamics in soil along an N processing gradient within a mixed hardwood dominated watershed at Fernow Experimental Forest, West Virginia. Sites were designated as LN (low rates of N processing), ML (moderately low), MH (moderately high), and HN (high). Soils underwent three 7-day freezing treatments (0, –20, or –80 °C) in the laboratory. Responses varied between temperature treatments and along the gradient. Initial effects differed among freezing treatments for net N mineralization, but not nitrification, in soils across the gradient, generally maintained at LN < ML ≤ MH < HN for all treatments. Net N mineralization potential was higher following freezing at –20 and –80 °C than control; all were higher than at 0 °C. Net nitrification potential exhibited similar patterns. LN was an exception, with net nitrification low regardless of treatment. Freezing response of N mineralization differed greatly from that of nitrification, suggesting that soil freezing may decouple two processes of the soil N cycle that are otherwise tightly linked at our site. Results also suggest that soil freezing at temperatures commonly experienced at this site can further increase net nitrification in soils already exhibiting high nitrification from N saturation.

Wounding of aspen roots promotes suckering

2004 ◽  
Vol 82 (3) ◽  
pp. 310-315 ◽  
Author(s):  
Erin C Fraser ◽  
Victor J Lieffers ◽  
Simon M Landhäusser
Keyword(s):  
Populus Tremuloides ◽  
Growth Rates ◽  
Growing Season ◽  
Organic Layer ◽  
Trembling Aspen ◽  
Layer Depth ◽  
Injury Type ◽  
Organic Layers ◽  
Root Injury ◽  
Root Sucker

In early May, 1-m sections of trembling aspen (Populus tremuloides Michx.) roots in a forest cutblock were carefully exposed and examined for damage. Undamaged roots were subjected to one of three wounding treatments (scrape, sever, or uninjured control) and were then reburied to either the full normal organic layer depth or to one third of the normal depth. Following one growing season, the roots were reexposed and assessed for aspen sucker numbers and growth rates. Results indicate that injured roots produced suckers nearly twice as often as uninjured roots. Further, injured roots produced more suckers per root, and these suckers were taller and had greater leaf area. Roots buried under shallow organic layers also generated more suckers, regardless of injury type. The side of injury (distal or proximal) did not affect any of the measured variables. The present study suggests that moderate wounding of aspen roots increases initial sucker numbers and growth rates.Key words: trembling aspen, root sucker, root injury, regeneration.

Effect of landscape position on N mineralization and nitrification in a forested watershed in the Adirondack Mountains of New York

1999 ◽  
Vol 29 (4) ◽  
pp. 497-508 ◽  
Author(s):  
Kiyokazu Ohrui ◽  
Myron J Mitchell ◽  
Joseph M Bischoff
Keyword(s):  
New York ◽  
N Mineralization ◽  
Forest Floor ◽  
Landscape Position ◽  
Nitrification Rate ◽  
Forested Watershed ◽  
Net N Mineralization ◽  
Adirondack Mountains ◽  
Net Nitrification ◽  
Intermediate Rate

Within a forest ecosystem in the Adirondack Mountains of New York, net N mineralization and nitrification rates were measured at different landscape positions (zones). Net N mineralization rates (0-15 cm depth) were less (39 kg N·ha-1 per year) within a wetland without alder and with a coniferous overstory than an upland conifer zone (82 kg N·ha-1 per year) and an upland hardwood zone (107 kg N·ha-1 per year). Net N mineralization rates (39 to 82 kg N·ha-1 per year) and the forest floor N concentrations (2.3 to 2.5%) were higher than values reported (1.2-29 kg N·ha-1 and 1.1-2.12%, respectively) for other spruce forests. The net nitrification rates were higher at the upland hardwood zone (29 kg N·ha-1 per year) than the upland conifer zone (2 kg N·ha-1 per year). The wetland conifer zone without alders had an intermediate rate of net nitrification (13 kg N·ha-1 per year) compared with the upland zones. The presence of white alder (Alnus incana (L.) Moench) in the wetland increased the NO3- content and net nitrification rate of the soil.

scholarly journals Reviews and syntheses: measuring ecosystem nitrogen status – a comparison of proxies

2016 ◽  
Vol 13 (18) ◽  
pp. 5395-5403 ◽  
Author(s):  
Maya Almaraz ◽  
Stephen Porder
Keyword(s):  
N Mineralization ◽  
Nitrogen Availability ◽  
N Availability ◽  
Net N Mineralization ◽  
Tropical Regions ◽  
Net Nitrification ◽  
Kendall’S Τ ◽  
Soil Δ15n ◽  
N Status

Abstract. There are many proxies used to measure nitrogen (N) availability in watersheds, but the degree to which they do (or do not) correlate within a watershed has not been systematically addressed. We surveyed the literature for intact forest or grassland watersheds globally, in which several metrics of nitrogen availability have been measured. Our metrics included the following: foliar δ15N, soil δ15N, net nitrification, net N mineralization, and the ratio of dissolved inorganic to organic nitrogen (DIN : DON) in soil solution and streams. We were particularly interested in whether terrestrial and stream based proxies for N availability were correlated where they were measured in the same place. Not surprisingly, the strongest correlation (Kendall's τ) was between net nitrification and N mineralization (τ  =  0.71, p < 0.0001). Net nitrification and N mineralization were each correlated with foliar and soil δ15N (p < 0.05). Foliar and soil δ15N were more tightly correlated in tropical sites (τ  =  0.68, p < 0.0001), than in temperate sites (τ  =  0.23, p  =  0.02). The only significant correlations between terrestrial- and water-based metrics were those of net nitrification (τ  =  0.48, p  =  0.01) and N mineralization (τ  =  0.69, p  =  0.0001) with stream DIN : DON. The relationship between stream DIN : DON with both net nitrification and N mineralization was significant only in temperate, but not tropical regions. To our surprise, we did not find a significant correlation between soil δ15N and stream DIN : DON, despite the fact that both have been used to infer spatially or temporally integrated N status. Given that both soil δ15N and stream DIN : DON are used to infer long-term N status, their lack of correlation in watersheds merits further investigation.

Regional variability in nitrogen mineralization, nitrification, and overstory biomass in northern Lower Michigan

1989 ◽  
Vol 19 (12) ◽  
pp. 1521-1526 ◽  
Author(s):  
Donald R. Zak ◽  
George E. Host ◽  
Kurt S. Pregitzer
Keyword(s):  
N Mineralization ◽  
Hardwood Forests ◽  
Net N Mineralization ◽  
Northern Hardwood Forests ◽  
Northern Hardwood ◽  
Net Nitrification ◽  
Biomass Increment ◽  
Annual Biomass ◽  
Oak Ecosystem ◽  
Northern Hardwood Ecosystem

Potential net nitrogen (N) mineralization, potential net nitrification, and overstory (boles and branches) biomass were measured in nine forest ecosystems commonly found within the well-drained uplands of northern Lower Michigan. The ecosystem types ranged from oak-dominated forests on coarse-textured outwash sands to mesic northern hardwood forests on sandy glacial till. Overstory biomass was calculated using species-specific allometric equations developed for Lake States hardwood species. Potential net N mineralization and potential net nitrification were measured by a 30-day aerobic laboratory soil incubation. Analyses of (co)variance were used to determine differences in potential N mineralization, net nitrification, overstory biomass, and biomass increment among the nine ecosystem types. Linear and nonlinear regression analyses were used to predict overstory biomass and biomass increment using potential net N mineralization as the independent variable. Overstory biomass ranged from 92 t•ha−1 in a xeric oak ecosystem to 243 t•ha−1 in a northern hardwood ecosystem; annual biomass production ranged from 1.3 to 3.5 t•ha−1 year−1, respectively. Potential net N mineralization was lowest in the xeric oak ecosystem (52.0 μg N•g−1) and greatest in the mesic northern hardwood ecosystem (127.8 μg N•g−1). Potential net nitrification was 45.5 μg NO3−-N•g−1 in the northern hardwood ecosystem; 10 to 230 times greater than in other ecosystems. A saturating exponential model (y = a(1–e−kx) + c) produced the smallest residual mean squares in predicting overstory biomass (R2 = 0.822) and annual biomass increment (R2 = 0.847) from potential net N mineralization. Maximum overstory biomass and biomass increment predicted from this equation were 247 t•ha−1 and 3.7 t•ha−1, respectively. In addition, laboratory net N mineralization potentials were highly correlated with annual rates of N mineralization determined by insitu incubation (r2 = 0.849). Overstory biomass and woody biomass increment were poorly correlated with potential net nitrification. The exponential function used to predict biomass increment from N mineralization suggests that the productivity of some northern hardwood forests in northern Lower Michigan is not limited by N availability.

Variation with slope aspect in effects of temperature on nitrogen mineralization and nitrification in mineral soil of mixed hardwood forests

2015 ◽  
Vol 45 (7) ◽  
pp. 958-962 ◽  
Author(s):  
Frank S. Gilliam ◽  
Julia E. Galloway ◽  
Jacob S. Sarmiento
Keyword(s):  
N Mineralization ◽  
Incubation Temperature ◽  
Global Climate ◽  
Mineral Soil ◽  
Slope Aspect ◽  
Net N Mineralization ◽  
Inorganic N ◽  
N Dynamics ◽  
Net Nitrification ◽  
Effects Of Temperature

This study examined the effects of temperature on soil nitrogen (N) dynamics and variation with slope aspect (northeast (NE) versus southwest (SW)) at two forested sites in West Virginia — Beech Fork Lake (BFL) and Fernow Experimental Forest (FEF) — with similar soil and overstory characteristics but with different latitudes and elevations. Previous work on mineral soil from both sites had shown sharp differences in microbial communities between SW slopes and NE slopes. Mineral soil was sampled from three and eight plots per aspect at FEF and BFL, respectively. Inorganic N was extracted from samples, which were then divided into polyethylene bags for 7-day incubations at 4 °C, 15 °C, 25 °C, and 35 °C. Following incubation, soils were extracted and analyzed for inorganic N. Net N mineralization varied significantly between aspects and temperatures but did not vary between sites; net nitrification varied significantly between aspects, temperatures, and sites. Net N mineralization increased with incubation temperature at all aspects and sites. Net nitrification rates increased with incubation temperature for BFL soils; however, maximum net nitrification rates occurred at 20–25 °C for FEF soils. Net nitrification was essentially undetectable for SW soils at either site. Results underline the complexities of the N cycle in temperate forest ecosystems, representing challenges in predicting alterations in soil N dynamics under conditions of global climate change.

REGRESSIONS FOR ESTIMATING STRAW YIELDS AND N AND P CONTENTS OF SPRING WHEAT AND N MINERALIZATION IN A BROWN LOAM SOIL

1988 ◽  
Vol 68 (2) ◽  
pp. 337-344 ◽  
Author(s):  
C. A. CAMPBELL ◽  
R. P. ZENTNER ◽  
F. SELLES
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Spring Wheat ◽  
N Mineralization ◽  
Soil Moisture Content ◽  
N Uptake ◽  
Growing Season ◽  
Net N Mineralization ◽  
Loam Soil ◽  
Growing Season Precipitation

Data from an 18-yr crop rotation study carried out on a Brown loam soil at Swift Current, Saskatchewan, were used to estimate equations that relate spring wheat straw yields, and N and P content of grain and straw to moisture use (MU). Moisture use was defined as soil moisture content in 0- to 120-cm depth at seeding, less soil moisture content at harvest, plus growing season precipitation. Grain yields were also related to straw yields and to N content of the straw. Potential net N mineralization (Nmin) in summerfallow (periods during the growing season with negative Nmin omitted) was related (r = 0.74**) to precipitation received during the spring to fall period. An attempt to relate apparent net Nmin (determined by N balance) in cropped systems to growing season precipitation or to MU was not successful. Highly significant linear regressions were obtained for straw yields, grain N and P contents vs. MU, and for grain yield vs. straw yield (r = 0.66** – 0.83**), but the other relationships were less reliable (r = 0.41** – 0.55**) though still significant. We discussed how these relationships might be used to estimate fertilizer N requirements, for examining N immobilization-mineralization, and for estimating residue sufficiency for erosion control on summerfallowed land. Key words: Straw:grain ratio, N uptake, P uptake, crop residues, N mineralization

Weekly xylem production in trembling aspen (Populus tremuloides) in response to artificial defoliation

2004 ◽  
Vol 82 (5) ◽  
pp. 590-597 ◽  
Author(s):  
Brin Jones ◽  
Jacques Tardif ◽  
Richard Westwood
Keyword(s):  
Populus Tremuloides ◽  
Radial Growth ◽  
Regression Models ◽  
Wood Anatomy ◽  
Ring Width ◽  
Growing Season ◽  
Early Growth ◽  
Trembling Aspen ◽  
Forest Sites ◽  
Significant Difference

The present study investigated the effect of artificial defoliation on weekly radial xylem production in trembling aspen (Populus tremuloides Michx.). It was hypothesized that defoliated trees would show reduced xylem and vessel production and thinner secondary walls in fibres. Two adjacent natural forest sites were selected within Winnipeg, Manitoba. Microcores were extracted weekly from the stems of 30 aspen trees from May to October 2002. Ten aspen trees were defoliated using pole pruners between 22 June and 6 July. Measurements included weekly xylem increment, annual vessel characteristics, and late growing season fibre dimensions. No significant difference in overall ring width was observed; however, trees from both groups showed a significant reduction in ring width in 2002. The ratio of radial growth in 2002 / radial growth in 2001 was significantly less in defoliated trees, suggesting a higher reduction in radial growth due to defoliation. Sigmoidal regression models suggested early growth cessation in defoliated trees. No significant differences in vessel characteristics were observed between groups; however, the diameter and lumen width of fibres was significantly reduced in defoliated trees. It is speculated that a shorter radial growing season may have led to a reduced cell elongation period. An early cessation of the radial growing season associated with a reallocation of carbohydrates to produce a second flush of leaves could explain the reduced size of fibres from defoliated trees.Key words: wood anatomy, diffuse porous, image analysis, radial growth, cell dimension, dendrochronology.

Impact of simulated aspen shoot blight on trembling aspen

2007 ◽  
Vol 37 (4) ◽  
pp. 719-725 ◽  
Author(s):  
P.V. Blenis
Keyword(s):  
Populus Tremuloides ◽  
Tree Height ◽  
Growing Season ◽  
Common Disease ◽  
Trembling Aspen ◽  
Mechanical Wounding ◽  
Tree Form ◽  
Shoot Blight ◽  
The Difference ◽  
Intensively Managed

Although aspen shoot blight (ASB), caused by Pollaccia americana Ondrej, is a common disease of trembling aspen ( Populus tremuloides Michx.), its impact is uncertain. Mechanical wounding, previously shown to be a reliable surrogate for ASB infection, was used to assess ASB impact in two experiments. In the first experiment, the effect of date of wounding on impact was studied by wounding 1-year-old aspen on four dates between 29 June and 10 August 2001. Tree form at the end of the 2001 growing season varied with wounding date, and for each of the wounding dates, tree height was reduced relative to that of unwounded, control trees. After the 2005 growing season, only trees wounded on 17 July were shorter than unwounded trees and the difference in heights was only 62 cm. In the second experiment, trees spaced at 2.0 or 0.67 m were wounded in four successive seasons to determine the effect of multiple years of infection on trees growing at different densities. Simulated ASB reduced tree height by an average of 16 cm, whereas branchiness was not increased by ASB, even at the lower density. Although ASB should not be ignored, these results suggest that it is unlikely to be amongst the most destructive pests of intensively managed aspen.

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